BaseGDL* sem_create(EnvT *e)
{
SizeT nParam = e->NParam(1); // 1 is the minimal number of parameter required
DString name;
e->AssureStringScalarPar(0, name); // IDL accepts null-string name
int destroyIx = e->KeywordIx("DESTROY_SEMAPHORE");
bool destroyKWPresent = e->KeywordPresent(destroyIx);
DLong destroy = 0;
if (destroyKWPresent)
{
destroy = (*e->GetKWAs<DLongGDL>(0))[0];
}
bool owner = true;
#if defined(_WIN32) && !defined(__CYGWIN__)
// TODO: Needs error handling with name length > 256
const char* cname = name.c_str();
WCHAR tname[256] = {0,};
MultiByteToWideChar(CP_ACP, MB_PRECOMPOSED, cname, strlen(cname), tname, 256);
HANDLE sem = CreateSemaphoreW(NULL,1,1,tname);
if (sem == NULL) {
owner = false;
return new DIntGDL(0);
}
#else
sem_t *sem = sem_open(name.c_str(), O_CREAT | O_EXCL, 0666, 1);
if (sem == SEM_FAILED)
{ // semaphore exists. make another one, locked (value=0)
owner = false;
if (errno == EEXIST)
{
sem = sem_open(name.c_str(), O_CREAT ,0666, 0);
}
if (sem == SEM_FAILED)
{
return new DIntGDL(0);
}
}
#endif
// Behavior for different values of DESTROY_SEMAPHORE:
// DESTROY_SEMAPHORE | owner | other (== !owner)
// ------------------+----------+-----------
// not set | delete | ignore
// != 0 | delete | delete
// 0 | ignore | ignore
sem_data_t data;
data.sem = sem;
sem_set_owner(data, owner);
sem_set_deletable(data, (!destroyKWPresent && owner) || (destroy != 0));
sem_set_locked(data, false);
sem_add(name, data);
return new DIntGDL(1);
}
BaseGDL* sem_create(EnvT *e)
{
SizeT nParam = e->NParam(1); // 1 is the minimal number of parameter required
DString name;
e->AssureStringScalarPar(0, name); // IDL accepts null-string name
int destroyIx = e->KeywordIx("DESTROY_SEMAPHORE");
bool destroyKWPresent = e->KeywordPresent(destroyIx);
DLong destroy = 0;
if (destroyKWPresent)
{
destroy = (*e->GetKWAs<DLongGDL>(0))[0];
}
bool owner = true;
#ifdef _MSC_VER
HANDLE sem = CreateSemaphore(NULL,1,1,name.c_str());
if (sem == NULL) {
owner = false;
return new DIntGDL(0);
}
#else
sem_t *sem = sem_open(name.c_str(), O_CREAT | O_EXCL, 0666, 1);
if (sem == SEM_FAILED)
{
owner = false;
if (errno == EEXIST)
{
sem = sem_open(name.c_str(), 0);
}
if (sem == SEM_FAILED)
{
return new DIntGDL(0);
}
}
#endif
// Behavior for different values of DESTROY_SEMAPHORE:
// DESTROY_SEMAPHORE | owner | other (== !owner)
// ------------------+----------+-----------
// not set | delete | ignore
// != 0 | delete | delete
// 0 | ignore | ignore
sem_data_t data;
data.sem = sem;
sem_set_owner(data, owner);
sem_set_deletable(data, (!destroyKWPresent && owner) || (destroy != 0));
sem_set_locked(data, false);
sem_add(name, data);
return new DIntGDL(1);
}
void sem_release(EnvT *e)
{
SizeT nParam = e->NParam(1);
DString name;
e->AssureStringScalarPar(0, name);
sem_data_t data = sem_get_data(name, e);
if (sem_is_locked(data))
{
sem_set_locked(data, false);
sem_post(data.sem);
}
}
BaseGDL* sem_lock(EnvT *e)
{
SizeT nParam = e->NParam(1);
DString name;
e->AssureStringScalarPar(0, name);
sem_data_t &data = sem_get_data(name, e);
if (sem_is_locked(data))
{
// lock already held
return new DIntGDL(1);
}
if (sem_trywait(data.sem) == 0)
{
sem_set_locked(data, true);
return new DIntGDL(1);
}
return new DIntGDL(0);
}
